Apparatus for manufacturing insulated wire



July 28, 1942.

" S. T. P OWELL APPARATUS FOR MANUFACTURING INSULATED-WIRE 'Filed .June 11, 1941 lil l r-wventor Samuel T. 1f .v\/el|- His Attorney.

Patented July 28, 19.42

APPARATUS Foa MANUFAc'rURmG INsULATEn WIRE Samuel T. Powell, Fairlield, Conn., assignor' to General Electric Company, a corporation c New York Application June 11, 1941, Serial No. 397,585

5,Cla.ims.` (Cl. 18-6) My invention relates to the manufacture of insulated wire by a continuous process and more particularly to the manufacture of wire having a vulcanizable coating by a continuous curing or vulcanizing process.

The object of my invention is to provide an improved apparatus lfor the manufacture of insulated wire, particularly apparatus for increasing the speed with which the Wire covering may be cured with a resulting improvement in the product.

In the accompanying drawing, Fig. 1 is a diagrammatic view of an apparatus embodying my invention for curing a wire coated withvulcanizable material; Fig. 2 is a sectional view through the entrance end of the vulcanizing apparatus; Fig. 3 is a sectional view through a vulcanizing chamber taken along the line 3-3 of Fig. 2; Fig. 4 is a sectional view through the exit end of the vulcanizing apparatus; Figs.'5 and 6 are sectional views through the vulcanizing chamber showing modications thereof; and Fig. 7 is a sectional view taken along the line 1--1 of Fig. 5.

In the manufacture of insulated wire coated with a vulcanizable material a continuous process has been utilized in curing extremely long lengths of coated wire. Such process employs apparatus shown diagrammatically by Fig. i, which includes an extrusion press l and a vulcanizing chamber Il closed at opposite ends by entrance and exit seals l2 and I3, respectively, together with means for passing the coated wire Lthrough the vulcanizing chamber including a pay-ofi capstan i4 and a take-up capstan i5. The wire to be insulated is drawn from the capstan I4 through the extrusion press I0, where the vulcanizable coating is applied thence through the entrance seal I2 into the vulcanizing chamber Il. After being `vulcanized, the coated wire passes through exit seal i3 and is Wound around the take-up capstan I5. Usually, the vulcanizing medium employed in the chamber Il is steam which is fed to the chamber through a plurality of inlet pipes I6, two of which have been shown although the number of inlet pipes may be varied depending upon the length of .the vulcanizing chamber.

Vulcanizing chambers used with the apparatus vdescribed areof considerable length to provide a sulciently long period of contact between the vulcanizing medium and the coated wire to insure complete curing as the wire is passed continuously through `the chamber since theV wire capstan l5'. In some instances, the chamber may be as long as 200 feet or more.

Custcznarily, the vulcanizing chamber H is disposed in a horizontal plane due to its great length. When so disposed, it will be apparent that the ste'am condensate caused by cooling during vulcanization of the coating will collect along the 'bottom of the chamber and will flowv along the length of the chamber to drain openings provided adjacent the seals at each end of the chamber. In former constructions of the apparatus, the coated conductor was entirely unsupl ported throughout the length of the vulcanizing chamber Il'. Consequently, it dragged along the bottom of the chamber since it could not be put under sumcient tension to maintain it above the bottom of .the chamber due to the plastic condition of the vulcanizable coating upon entering the chamber. This meant that the coated conductor was partially immersed in' the pools of condensate which collected at various points along .the bottom of the vulcanizing chamber. Since the condensate, due to heat losses in the Wire and vulcanizing chamber, is ordinarily at a considerably lower temperature than that of the vulcanizing steam, the 'speed of vulcanization of the coating was seriously impaired due to the fact -that the coating was surrounded at many points along its length by the comparatively low temperature condensate rather than by the high temperature steam. 'I'his resulted in the necessity for increased curing time reducing the speed at which the wire could be passed through the chamber. In aggravated cases, blemishes might occur on Ythe surface of the coating. I propose to overcome these deficiencies by providing maens in the vulcanizing chamber to support the coated conductor out of contact with the condensate so that at all times it is surrounded by the high temperature vulcanizing medium.

Referring to Figs. 2 to 7 of the drawing, I have shown my invention applied to apparatus of the type described in the Forstrom and lHull Patent 2,069,087, assigned to the same assignee as the instant application. The arrangement of the entrance seal and vulcanizing chamber will now be brieiiy'described in relation to my invention; for a more detailed description of the sealing structure, reference may be made to the Forstrcm and Hull patent.

The entrance end ofthe vulcanizing chamber H is secured to a hollow head I1 on which the aforementioned entrance seal i2 is mounted. This seal comprises a. tube |18 containing a plumust be fully cured when wound on the takeTup .rality of glands i9 having openings therein for re- .threaded on the end of the tube. is threaded into a gland 2| which in turn is mounted in position on the head I'I by a threaded chamber. i

In prior constructions, when thecoated wire' with the condensate in chamber.

ceiving the coated conductor. The glands are located in side by side relationship within the tube I8 and are held in position by a cap 28 The tube I8 nut 22. The gland 2| is provided with a plurality of annularly arranged openings 23 so that fluid from an inlet pipe 2| is accessible to the interior of the gland and tube I8. In order to conne `the vulcanizing medium in the chamber II and prevent it`^from entering the gland -23 and the tube I8, the uidis maintained at a pressure slightly higher than that o f the steam. Customarily, the sealing iiuid employed is water but in some cases, a gas may be employed. The water passes through the glands I9 along the tube I8, the glands being provided with enlarged openings 25 which restrict the flow of water and reduce the pressure along the length of the tube I8 so that when the water drains through an outlet opening 26, it is no longer under pressure. The number of glands employed in the tube I8 and the length of the tube forming the seal depend upon the pressure of the vulcanizing medium and the pressure of the sealing iluid. These will vary according to the particular installation. Referring to Fig. 4, it will be apparent that the exit end of the vulcanizing chamberV II is likewise provided with a sealing means which in all respects is similar to the entrance seal just described, the sealing liquid being fed to the seal through an inlet pipe 21.

The vulcanizing steam from the inlets I8 surrounds the coated conductor throughout the entire length ofthe vulcanizing chamber II and tube so that it is maintained out of contact with effect. a plurality- 'of surfaces supporting the coated wire out of contact with the steam co'ndensate.

In operation, any condensate caused by cooling of the steam in contact with the vulcanizable coating will formon the bottom of the liner 28 but. instead of collecting there in pools of sumcient size to cool the coating and impair the vulcanizing action of the steam, will immediately drain through the openings 8| to the bottom of the vulcanlzing chamber I I and thence along the wall of the chamberv to thedrain pipes 28. In this manner, the coated conductor is maintained out of contact with the condensate at all times so that there is no impairment of the vulcanizing action of the steam. It has been found in actual practice that by keeping the coated wire out of contact with the condensate, the rate of vulcanization of the wire is markedly increased with a corresponding improvement inthe quality of the vulcanizable coating. increase the speed at which the wire is drawn through the curing chamber with a resulting` saving in cost.

In some installations, the pressure of the vwater in the seais at the entrance and exit ends of the vulcanizing tube is such that a small amount of the water may drain intoy the headsl'l .and along asthe steam is cooled down during the vulcanizing process, the condensate collects on the bottom of the chamber and is drained oi! at either end by drain pipes 28.` If desired, drain pipes maybeplaced at Aintermediate points along the length of the vuicanizing chamber but for the Y purposes of illustration, the drain pipes Vhave been shown as located at opposite ends of the entered the vulcan'izing chamber, the weight o'f the wire caused it to sag downwardly in the manner indicated'by Figs. 2 and 4, so that it tended to rest `on the bottom of the chamber in contact densate tended to cool .down the coating on the wire; retarding the speed of cure. According to I my invention. however, means are provided for maintaining the coated conductor out of contact the bottom 0f theV To this end,'I provide the vulcanizing chamber with a hner, which in the form of the invention shown by Fig. 2, comprises a tube 28 having hns 3U-extending from its' exterior surface vfor enl gagement with the walls of the vulcanizing chamberso that the liner 28 is maintained spaced from lthe walls of the chamber. 'I'he tube isprovided avoid any rough spots which might damage the coating o'n the wir'e at the points where the .ends

A of*4 the tubes make contact with each other. The coated wire passes throughthe interior of the vwith the condensate. Since the condensate is at a lower temperature than the steam,v the con-g the ends of the vulcanizing chamber I I for arelatively short distance. Since this water'is at room temperature, it'would have an undue cooling effect on Athe vulcanizable coating were' it not for the fact that the liner 29 maintains the wire out of contact with any of the sealing liquid which may inadvertently enter chamber II. Normally, the small flow-of sealing liquid into the vulcanizing chamber is removed by the drain pipes 28 so that the'coat'ed wire is in contact with the water only during its passage through the seal. g

In Figs. 5 and 6, I have illustrated several modi-` iications of the structure of the liner. In the modification shown b y Fig. 5.a plurality of solid walled tubes' 88 are laid end to end within the vulcanizing chamber and the endsof the tubes are flared outwardly, as shown at 84, to position the tube centrally of the chamber and to provide smooth surfaces for the passage of the coated wire. The flared endslofthe tubes are provided 6, the liner is composed of a spiral spring, several of which may be laid end to end within the vulcanizing chamber.. The convolutions of the spring support the coated conductor at spaced points out of contact with the condensate. Since the cornersv of the spring convolutions are` What I` claim as new and desire to secure by Letters Patent of the United States, is:

1 .,In an apparatus for manufacturinginsu-- Moreover, it is possible to lated wire, an elongated horizontal vulcanizing through the openings in said tube and draining chamber, means for supplying steam to said Y chamber, means for passing a wire coated with vulcanizable material continuously through s'aid chamber, and a liner in said chamber supporting the coated wire, spaced from the bottom of said chamber, said liner being provided with spaced passageswhereby the steam condensate may flow therethrough tothe bottom of said chamber so that the vulcanizable coating is maintained out' of contact with the steam condensate.

2. In an apparatus for manufacturing insu'- lated wire by a continuous process, an elongated horizontal vulcanizing chamber, a liner for said chamber, said liner having supporting surfaces and extending along the length thereof, said supporting surfaces being separated from one another by passages, means for passing a wire coated with vuicanizable material continuously through said chamber, the wirebeing carried on Y the supporting surfaces of th'e liner out of contact with the said wall of thechamber and means for supplying steam to said chamber, the steam condensate passing through said passages and being collected along the bottom wall of said 'l5 spacedfrom the bottom wall of said chamber chamber out of contact with the vulcanizable 'y coating. l

3. In an apparatus for manufacturing insulated wire by a continuous process, an elongated horizontal vulcanizing chamber, a liner` for said chamber comprising a tubular member spaced from the walls of said chamber and being provided with a plurality of openings therein, means for supplying steam to said ch'amber and to the interior of said tubular member, and means for passing a wire coated with vulcanizable material continuously through said chamber, the wire passing through and being supported by saidl tubular member, the steam condensate passing to the bottom of said chamber out of contact with the vulcanizable coating.

4. In `apparatus for applying a covering to a wire, an elongated horizontal vulcanizing cham,

ber, means for supplying steam under pressure to said chamber, means for sealingopposite ends of said vulcanizlng chamber, a drain connected to said chamber for removing steam condensate, means for passing a wire coated with' vulcanizable material continuously through said sealing means and vulcanizing chamber, and lsupporting means in said vulcanizing chamber having a plurality of supporting surfaces spaced from the bottom wall of said chamber and extending along the length thereof, said supporting means beingprovided with a plurality-of openings, the coated wire being supported by and moving along the spaced surfaces within the vulcanizing'chamber in contact with the` steam but out of contact with the steam condensate which flows through said openings for collection on the bottom Wall of said vulcanizing chamber.

5. In apparatus for manufacturing insulated wire by a continuous process, an elongated vulcanizing chamber. means for supplyinglst'eam to r 

